This manifold only had about 15mm tower clearance. You will find that the engine will move only a little closer to the tower when driving. It more rotates a bit but not realy moving it too much closer.

I like the idea of having a straight section before the port. But the tight radius bends to come back over the rocker cover are less than ideal on this manifold.

It also has a 1.5 degree taper leading to the port over the last 220mm, ive read that this taper maximises velocity at the port. much more taper than this starts reducing the gains from a taper. http://datsun1200.com/uploads/photos/12251.jpg


If you go with quads, moving the throttle bodies further from the head enables the use of slightly larger throttle plates without losing midrange because a good taper can be included in the design. Giving less restriction at the plates and good air speed at the ports.